1. Field of the Invention
The present invention relates to tube connecting devices and in particular to such devices for releasably connecting together the ends of two tubes.
2. Background Art
A conventional tube connecting device comprises a generally tubular housing which, in use, is connected to one end of a pipe. The housing forms a tubular socket for receipt of an end of another pipe. The pipe received within the socket is releasably held therein by means of two pivotally mounted retaining arms, mounted diametrically opposite each other on the outer surface of the housing. The securing arms are pivotable through approximately a right angle from a securing position in which a projection on the arms extends through an aperture in the wall of the cylindrical socket and engages with a peripheral recess in the outer surface of the pipe to be retained, to an unsecured position in which the projection is withdrawn from the aperture and from the peripheral recess on the pipe, thereby allowing the pipe to be removed.
Various techniques are known for releasably securing the retaining arms in the locked position in order to prevent inadvertent disengagement of the pipe. In one arrangement each of the retaining arms is provided with a slot through which an apertured lug located on the exterior of the housing projects when the arm is in its locked position, in the manner of a hasp and staple connector. The arms can be held in position by passing a fastening ring, secured to the ends of the securing arms, through the staple. However, this arrangement is not particularly convenient to use and thus there is a risk that operators might be discouraged from securing the securing arms in the locked position.
An alternative arrangement referred to in U.S. Pat. No. 5,295,717 utilizes a spring-loaded positioning rod on each of the securing arms which, when the arms are in their locked position, engage with an associated blind bore in the housing of the device. The housing is also provided with an inclined flange with which the retaining rod engages as the securing arm is pivoted to its locked position, which causes the positioning rod to be displaced against the restoring force of the spring as the securing arm is pivoted, until the securing arm reaches its locked position, whereupon the positioning rod snaps into its associated recess. In order to pivot the securing arms to the open position the positioning rods are withdrawn out of their associated recesses against the force of the restoring springs, thereby allowing the securing arms to be pivoted. However, whilst this arrangement is an improvement over the first-mentioned arrangement, considerable physical effort can be involved in pivoting the securing arms to their closed position since the positioning rod must be displaced against the force of its associated restoring spring by means of a camming action against the inclined surface of the flange which itself introduces a considerable amount of friction.
In accordance with the first aspect of the present invention, a tube connecting device comprises a housing, a socket formed in the housing for receipt of a pipe or tube to be releasably secured therein, and a securing arm pivotally mounted to the housing and being pivotable from a first, locked position in which a portion of the arm projects through an associated aperture in the wall of the socket to engage a complementarily-shaped portion of the pipe to be retained, to a second, unlocked position in which the projecting portion of the securing arms is withdrawn from the socket, the device further comprising an actuator mounted on the arm and a locking member located in a chamber within the arm, the actuator being displaceable from a first, locking position in which it displaces the locking member partially out of the chamber and engages it with a recess in the housing to releasably retain the arm in the locked position, to an unlocking position in which the locking member is movable out of the recess, whereby the securing arm can be pivoted away from the locked position.
Preferably, the actuator projects into the chamber in which the locking member is located when in the first, locking position.
In one embodiment, there is a plurality of locking members.
The or each locking member may comprise a ball.
In another embodiment, the chamber is elongate and is dimensioned to allow movement of the or each locking member only along the chamber except during engagement with or disengagement from a recess in the housing. There may be a plurality of locking members in the chamber. The locking members in the chamber are preferably substantially identical.
In a further embodiment, the actuator engages two locking members. The actuator may be arranged to displace the two locking members in opposite directions into engagement with respective recesses in the housing.
The total length of the or each locking member in the direction of the chamber preferably does not exceed the length of the chamber.
Preferably, when the securing arm is pivoted away from its locked position, the or each locking member is located completely within the chamber.
The device may further comprise means for preventing the or each locking member from leaving the chamber when the arm is pivoted away from its locked position. The device may comprise an abutment member which opposes an open end of the chamber when the arm is pivoted away from its locked position. Conveniently, the or each recess for receipt of a locking member may be located in the abutment member. The abutment member preferably forms part of the housing.
In yet another embodiment, a mounting lug for the arm in which the chamber is located extends across an open end of the chamber and forms the abutment member. The device preferably comprises two mounting lugs between which the arm is mounted, each mounting lug being located across an open end of the chamber and forming an abutment member.
In a still further embodiment, the recess in the housing for engaging the locking member comprises a bore. The bore is preferably narrower than the locking member with which it is engageable.
The actuator comprises a retractable rod. The end of the rod is preferably tapered. The rod is preferably spring loaded towards its locking position. The device may further comprise a handle for withdrawing the actuator towards its unlocking position.
Preferably, the device comprises a plurality of said securing arms.
By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings.